c# .net website enhancement

I need programming support to keep my site running smoothly and address emergency issues. My web site has 3 major components: membership, products/services, and forum/communities. users can create a free membership to conduct business on my web site. The membership enrollment includes filling a profile of products and services the member can offer. Members can post products or services ads. It's similar to a classified ads database. There is no direct money transaction through the site. The users coordinate payments independently. The community page offers members with similar interest to create, join groups, and share their thought through community forums. I'd like to add backend programs that can track all the queries and activities in my web site, so I can know how users are using my site. I'd like to be able to generate reports or ask questions like: 1. Who searched for what? 2. What are the most popular searches? 3. How long do users stay on my site? 4. Which product or services has been read the most? 5. People who looked at this product also looked at that product. I also need to organize my database to make the web searches more efficient. Build a database of search keywords to be used as part of auto fill search (i.e. suggested search keywords based on characters entered in the search field). I am hoping to implement these features within 2-3 weeks of finalizing specifications.